Response when hearing hayya alas-salah in Adhan
لا حَـوْلَ وَلا قُـوَّةَ إِلاّ بِالله
لا حَـوْلَ وَلا قُـوَّةَ إِلاّ بِالله
La hawla wala quwwata illa billah
Translation
There is no might nor power except with Allah.
When to recite
Said when hearing "hayya alas-salah" or "hayya alal-falah" during the Adhan.
Source / Reference
Al-Bukhari 1/152, Muslim 1/288